Hand held tube bender

ABSTRACT

A tube bender is shown which has a handle on which is rotatably mounted a bending mandrel with a tube engaging hook swivably carried by the mandrel and with the mounting for the hook being a crank or eccentric so that when the mounting is rotated the hook is moved toward or away from the groove of the mandrel. The hook is also offset so that it may engage a tube close to the start of the bend point on the mandrel. The mandrel is rotatable on the handle and held in different positions thereon by a detent means. The bending shoe is on the end of a second handle and is pivotably connected to a link plate which is rotatably journalled on an annular bearing surface on the mandrel between the mandrel and the first handle.

llnited States Patent [1 1 Frank 111 Magma Feb. 5, 1974 HAND HELD TUBEBENDER [75] Inventor: Heinrich l-I. Frank, Amherst, Ohio [73] Assignee:Emerson Electric Co., St. Louis, Mo.

[22] Filed: Aug. 4, 1972 [21] Appl. No.1 278,077

[52] U.S. Cl.....'. 72/36, 72/388 Primary Examiner-Charles W. LanhamAssistant Examiner-Robert M. Rogers Attorney, Agent, or Firm.l. DarrellDouglass [5 7] ABSTRACT shown which has a handle on which is rotatablymounted a bending mandrel with a tube engaging hook swivably carried bythe mandrel and with the mounting for the hook being a crank oreccentric so that when the mounting is rotated the hook is moved towardor away from the groove of the mandrel. The hook is also offset so thatit may engage a tube close to the start of the bend point on themandrel. The mandrel is rotatable on the handle and held in differentpositions thereon by a detent means. The bending shoe is on the end of asecond handle and is pivotably connected to a link plate which isrotatably joumalled on an annular bearing surface on the mandrel betweenthe mandrel and the first handle.

18 Claims, W

HAND HELD TUBE BENDER BACKGROUND OF THE INVENTION 1. Field of theInvention The invention relates to hand held tubing or rod benders forenabling bends to be made in tubes or rods encompassing many degrees ofbends mostly from to 180 useful in the plumbing and refrigerationindustry or in any place where a tubing system is being constructed tocarry a liquid or a gas.

2. Description of the Prior Art The prior art is best exemplified in US.Pat. No. 3,194,038 and, as can be seen, usuallycomp rised a handle, tobe gripped by one hand and carrying on the end a generally circularmandrel having a groove in its periphery for receiving a tube to bebent.A bending shoe is carried on the end of a second handle and attached tothe mandrel by a link pivoted at one end on the axis of the mandrel andthe other end to the bending shoe and its handle. A tube is placed inthe groove of the mandrel with one end extending alongside the handleand the part to be bent extending in the groove tangent to the bottom ofthe groove. A holding hook pivoted at its base on the mandrel is swungover and holds the end of the tube that extends alongside the mandrel.The handle with the bending shoe is then swung around so that the shoeengages the tube at the place where the bend is to be started. Thehandle with the shoe is then rotated around the mandrel to bend the tubeinto the groove in the mandrel, the bend taking the curvature of thegroove in the mandrel. Usually bends from 0 to 180 may be made. In manybenders such as that of US. Pat. No. 3,194,038 when a 180 bend is made,the handles must be extended at the start of the bend so that they are180 apart as shown in FIG. 8 of that patent. This puts the operator at adisadvantage since it is extremely difficult, especially with hardtubing, to start a bend with the handles fullye xtended.

Another disadvantage of the prior art resided in the fact many of thesedevices, particularly in the type of bender the subject of thisapplication, the tube was held by a hook which obviously had to beengaged with tube after the tube was in place, and therefor hadtangential engagement with the tube. With this type of engagement therewas a tendency to flatten or dent the tube at the point of ergagement.

In addition, the tube engaging hook was so disposed that it was outwardof the place where the bend was started (zero point) and therefor thebend could not be started close to the end, with the result thatfrequently it was necessary to cut off the stub, where a joint was to bemade close to the bend, which was time consuming and wasteful ofmaterial. As can be seen from US. Pat. No. 3,194,038 the mandrel, aboutwhich the bend is made, is usually provided with a flat portion removedalong a chord into which the fixed handle is secured, and the hook isswivably mounted on the handle. In addition, it is frequently desirableto make a bend in a tube, which has a coupling on the end with the bendclose to the coupling. With the prior device the placement of the hookwas so far outward, and the coupling had to be outwardly of the hook,that a bend could notbe made close to the coupling.

SUMMARY OF THE INVENTION able the desired degree of adjustment.

This is accomplished by mounting the hook on a r0 tatable eccentricpivot so that the hook with its seat, which matches the periphery of thetube, may be swung over the tube and then rotated to bring the hook seatinto engagement with the tube surface.

In addition, the hook is so shaped that its seat engages with the tubeat a place close to the start of the bend.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. I, is an elevational view of the invention taken from one side andwith the handle broken away to forshorten the view;

FIG. 2, is a view from the end of FIG. 1;

FIG. 3, is a section taken on the line 3 3 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The bender includes a basehandle 10 which can be a stamping formed to provide a straight narrowhand grip part 10a of generally C shaped cross section and .then curves10b toward and ends in a generally circular end mandrel support portion10c. The end part 10c has a flat support surface 10d and has a centralpivot aperture We and in spaced concentric relation a series of detentapertures 10f each equally spaced from the pivot aperture and 45 apart.

A bending mandrel 20 is pivotally secured to the mandrel support andincludes circular a base 20a having a central stub shaft to provide apivot 20b disposed in the aperture 10e of the handle base and having astem 20c which extends through a washer 22 and may be headed over at20d. The length of the pivot part 20b is such that when the stem 20c isheaded over the base 20a is disposed close to the base 10d but is freeto revolve thereon. The mandrel is bored at 20f to provide a blindopening for the reception of an enlarged skirt 24 of a hollow detentplunger. The plunger has a head 24a of reduced size for engagement inany one of the detent apertures 10f in the base. A spring 26 disposed inthe plunger engages with the bottom of the bore and the inner end of thehollow plunger to hold it pressed toward the base 100. Thus the head ofthe detent plunger, which is chamfered, may be pressed inward to free itfrom locking engagement with any of the apertures and the mandrelrotated to any of the positions 45 apart.

Although five apertures 10f have been shown, it is apparent that more orless holes could be provided and allow themandrel to be rotated in 45increments to any position relative to the base handle. In practice ithas been found that four such apertures will usually en- The base a ofthe mandrel is surmounted by an enlarged body 20g of generally circularform except at the place 2011 where a portion is removed along a chordto provide a seat where a tube holding hook is attached, later describedin detail. The periphery of the body 203 is formed with a tube receivinggroove 20j of generally semi-circular cross-section although itpreferably has a I80 bottom portion merging with straight sidewallswhich assist in preventing flattening of a tube during a bendingoperation as is well known in the art. The groove intersects the placewhere the material is removed at the chord 20h.

The tube holding hook, as can best be seen from FIGS. 1 and 2, whichshows it in tube engaging position, comprises an apertured base 30extending outwardly of the face of the mandrel and then bends at a rightangle at 30a to provide a portion 30b which again bends downward toextend over the face of the mandrel and then a bend 30c to provide apart 30d which extends over and opposite the periphery of the mandreland terminates in a hook 30e which is opposite the mandrel groove 20j.Opposite to the mandrel groove, the hook is formed with a semi-circulartube engaging surface 30f. It will thus be seen that the hook is C shapein profile when viewed from the end, FIG. 2, and Z shape in profile whenviewed from the side, FIG. I.

The hook is held on the seat 2012 of the mandrel by an adjustable pivotmember which includes a cylindrical body 40 disposed in a blind bore 20kthat extends into the mandrel from the seat 20h on a diameter of themandrel. On its outer end the body is provided with an eccentricallydisposed circular portion 40a of reduced diameter which extends throughthe apertured base 30 of the tube holding hook and terminates in aknurled knob 40b pressed onto the end of the eccentric part 40a thuslyholding the hook against the seat and on the adjusting member. The endportion of the adjusting member, within the bore, is of reduced diameterat 40c providing perpendicular side walls flanking the part of reduceddiameter. The center of the mandrel is drilled at 20m to provide a blindhole at the bottom of which is disposed a spring pressed plunger 42,which is a hollow body with a spring 44 having one end disposed in thebody and engaging the other end of the bore to urge the plunger againstthe reduced part 40c of the adjusting member. The part 400 is formedwith a pair of diametrically opposed flats 40d which provide seats forthe plunger 42 thus enabling the pivot member to be held in any one oftwo adjusted positions 180 apart. The plunger indexes the position ofthe pin 40 and also retains the pin in position. A hole 40f through theflats 40d allows a tool to be inserted to depress the plunger shouldremoval be desired. As can best be seen from FIG. 1, the adjustablemember is shown in a position where the hook 30e is closest to thegroove in the mandrel and it may be rotated 180 from the position shownto cause the hook to move outwardly of the mandrel.

tends outwardly beyond the periphery of the mandrel as best shown inFIG. 1. At the outer end of the link the bending shoe 50 is securelyconnected to the link by a headed pin 54. A roll pin 56 set into thelink, is disposed in the path of rotation of the shoe 50 and its handleand is engaged by the shoe when the handle is rotated clockwise to causethe shoe and link to attain a fixed position relative to each otherduring a bending operation. The shoe has a bending groove 50c extendinglongitudinally on its face opposite to the groove 20j in the mandrel.

In operation the mandrel is first set to the desired position for thedegrees of bend to be made. The position of the parts as shown in FIG. 1is not necessarily the position that would be taken at the start of anormal bending operation since the parts are shown in position forbetter illustration of the components. However it could be used, butwould require moving the shoe handle across the mandrel handle if therewas an aperture 10f to receive the mandrel detent 24 in the positionshown. Therefor it will be assumed that there is a first detentreceiving apertures 10f and that the detent 24 will be depressed and themandrel rotated counter-clockwise to the next detent aperture 10f for a45 bend.

It will be noted that the free end of the detent 24 is chamfered andtherefor it need not be fully depressed but merely depressed far enoughfor the chamfered edge to engage with the inner face edge of an aperture10f and movement will cause it to be cammed to the right (FIG. 3) and itwill ride on the face 10d of the base while the mandrel is rotated untilthe detent finally becomes aligned with one of the apertures 10f atwhich time it will snap into the aperture and provide a fixed alignmentof the mandrel with the handle 10.

The mandrel having been moved to the position described, the hook isrotated about its pivot to a position perpendicular to the mandrel. Theshoe handle is then swung from the position shown outward and a tubeinserted in the mandrel groove. The tube can be laid in the spacebetween the shoe and mandrel with a place or marking on the tubeopposite the 0" degree reference point. This can easily be done becausethe hook and shoe have been moved to positions to allow free access tothe groove.

It will be assumed the the knob 40b has bee rotated 180 degrees, fromthe position shown in FIG. 1, to

cause the hook to be moved outwardly of the mandrel, this being theposition it was adjusted to when the last tube that was bent was takenout. The hook can now be swung about its pivot 40b to the position shownin FIG. 1, over the tube that is to be bent. At this time theintermediate part of the hook lies against the face of the mandrel. Theknob 40b is then rotated I which draws the hook back toward the mandrelwith the seat 30]" of the hook in engagement with the periphery of thetube and holding this tube in the bottom of the mandrel groove. It willbe noted that the seat 30f provides as much or more than of contact withthe tube as contrasted to the prior art which had tangent contact withthe tube. Thus, since there is considerable pressure on the tube at thispoint during the bending operation, due to the extended area of contactthere is less tendency to nick or flatten the tube.

The shoe handle is then rotated clockwise unitl it engages with theprojection pin 56. At this time the groove 50c in the shoe engages withthe periphery of the tube and presses it into the mandrel groove 20j.The

is. "libs-f shoe handle 50a, which is now 45 removed from the basehandle, is moved toward the base handle which causes the shoe to followthe periphery of the mandrel and bend the tube, as it slides along thetube, to the contour of the mandrel groove. The markings on the mandreland the shoe enable the operator to determine the exact number ofdegrees of bend that have been made. It is pointed out that the markingsillustrated are bends most commonly made and that there could be moremarkings than shown that would provide a greater variance in the degreesof bend to be made.

It will thus be seen that because of the Z shape of the tube holdinghook, the tube is held at a place closer to the point where a bend isstarted. This enables tubes with a coupling such as C (FIG. l) to bebent close to the coupling and results in less wastage of tube when abend has to be made close to the end.

It is also apparant that a considerable advantage is realized when bendsof greater than 90 are to be made. For instance on 180 or 135 bends, thehandles would ordinarly be 180 to 135 apart. With the handles 180 apart,the least pressure can be exerted on the handles to bring them together.Obviously the greatest bending pressure can be realized the closer thehandles are together.-Therefor in making a 135 or larger bend, it isexpedient to set the tool for 45, make a 45 bend, then release the basehandle from the mandrel and move it another 45 and continue the bend.Thus bends up to 180 can be made easily and quickly because of the factthat the rotated position of the mandrel on the base handle can bequickly and easily changed.

As can best be seen from FIG. 3, the base handle is spaced from the shoehandle. This allows the shoe handle to cross over the base handle ifdesired. For ina 90 bend, bends up to 180 could be made by causing theshoe handle to pass over the base handle.

I claim:

1. A tube bending tool having a first handle, a substantially circularmandrel rotatably secured on the end of the said handle and having aperipherial groove, means cooperating with the handle and mandrel toquickly and adjustably fix the position of the mandrel on the handle, a.tube holding hook arranged to hold a tube opposite the groove in themandrel, a second handle having a tube bending shoe pivotally connectedto the first handle and mandrel, said shoe being having a bendingsurface movable along the periphery of the mandrel by said handle tobend the tube to the contour of the. groove in the mandrel.

2. A tool as described in claim 1 wherein said mandrel has a portionremoved along a chord to provide a seat for said hook and said hook ispivotally secured on the seat.

3. A tool as described in claim 2 wherein a pivot means is provided onsaid hook seat and said hook is journalled on said pivot means.

4. A tool as described in claim 3 wherein said pivot means comprises amember rotatably journalled in said mandrel and has an eccentric portionof reduced diameter upon which the hook is journalled, extending beyondsaid hook seat.

5. A tool as described in claim 4 wherein a control knob is provided onthe end of said eccentric portion to hold Said hook ersaa ns .stablsthaair lz ea 6. A tool as described in claim 4 wherein index meansis provided in said mandrel for engagement with said pivot means toindex the pivot means in at least two po- 'sitions.

7. A tool as described in claim 6 wherein said hook has a portionextending over the face of the mandrel and beyond the edge thereof and asecond portion extending opposite to the mandrel groove at the peripheryof the mandrel.

'aTA'EBBTaKHsCnBd in clairn 7 wherein the portion of the hook extendingopposite the groove in the mandrel is provided with a tube engaging seathaving substantially the same curvature as the transverse periphery of atube to be bent.

y Tmm'fi claim 7 wherein said hook where it extends over the face of themandrel and beyond the edge thereof, has the part opposite the mandrelgroove close to the start of a bend point for a tube.

12. A tool as described in claim 11 wh erein said re duced portion isformed with a pair of flats on opposite sides for engagement by thedetent means to index the pivot means at points apart.

' A toarasaa ema'i'aaaawherein said first handle has a circular endportion against which the mandrel is seated and said mandrel is formedwith an indented bearing surface adjacent said circular end portion andsaid pivoted connection for the bending shoe and its handle to the firsthandle includes a link having a ring portion disposed on said bearingsurface between the mandrel and said circular end portion and anoutwardly extending portion pivotally connected to said second handle. YW V v V V 7 14. A tool as described in claim 13 where said link has aprojection extending in the path of travel of said pivoted shoe toengage the shoe and hold the shoe and link in predetermined relation toeach other during a bending operation.

153E601 as described in claim 14 wherein said projection on the link isa pin set into the link and extending outwardly from the face thereof.

16. A tool as described in claim 1 wherein said first handle divergesfrom the second handle.

17. A tool as described in claim 1 wherein said first handle has acircular end portion against which the mandrel is seated and said endportion is formed with a series of apertures disposed equi-distant fromthe axis and said mandrel carries a detent means for selective engagmentin any one of the apertures.

18. A tool as described in claim 17 wherein said detent means is aspring pressed means disposed within the mandrel and has a reduceddiameter part extended outwardly therefrom for engagment in theapertures.

1. A tube bending tool having a first handle, a substantially circularmandrel rotatably secured on the end of the said handle and having aperipherial groove, means cooperating with the handle and mandrel toquickly and adjustably fix the position of the mandrel on the handle, atube holding hook arranged to hold a tube opposite the groove in themandrel, a second handle having a tube bending shoe pivotally connectedto the first handle and mandrel, said shoe being having a bendingsurface movable along the periphery of the mandrel by said handle tobend the tube to the contour of the groove in the mandrel.
 2. A tool asdescribed in claim 1 wherein said mandrel has a portion removed along achord to provide a seat for said hook and said hook is pivotally securedon the seat.
 3. A tool as described in claim 2 wherein a pivot means isprovided on said hook seat and said hook is journalled on said pivotmeans.
 4. A tool as described in claim 3 wherein said pivot meanscomprises a member rotatably journalled in said mandrel and has aneccentric portion of reduced diameter upon which the hook is journalled,extending beyond said hook seat.
 5. A tool as described in claim 4wherein a control knob is provided on the end of said eccentric portionto hold said hook thereon and enable the pivot means to be turned.
 6. Atool as described in claim 4 wherein index means is provided in saidmandrel for engagement with said pivot means to index the pivot means inat least two positions.
 7. A tool as described in claim 6 wherein saidhook has a portion extending over the face of the mandrel and beyond theedge thereof and a second portion extending opposite to the mandrelgroove at the periphery of the mandrel.
 8. A tool as described in claim7 wherein the portion of the hook extending opposite the groove in themandrel is provided with a tube engaging seat having substantially thesame curvature as the transverse periphery of a tube to be bent.
 9. Atool as described in claim 7 wherein said hook, where it extends overthe face of the mandrel and beyond the edge thereof, has the partopposite the mandrel groove close to the start of a bend point for atube.
 10. A tool as described in claim 6 wherein said mandrel isprovided with a bore for said pivot means and a second bore for theindex means and said pivot means has a pair of flats and a detent meansis disposed in the second bore and spring pressed toward the pivotmeans.
 11. A tool as described in claim 10 wherein said pivot means hasa portion of reduced diameter and said detent means engages said portionto hold the pivot means in the bore.
 12. A tool as described in claim 11wherein said reduced portion is formed with a pair of flats on oppositesides for engagemenT by the detent means to index the pivot means atpoints 180* apart.
 13. A tool as described in claim 1 wherein said firsthandle has a circular end portion against which the mandrel is seatedand said mandrel is formed with an indented bearing surface adjacentsaid circular end portion and said pivoted connection for the bendingshoe and its handle to the first handle includes a link having a ringportion disposed on said bearing surface between the mandrel and saidcircular end portion and an outwardly extending portion pivotallyconnected to said second handle.
 14. A tool as described in claim 13where said link has a projection extending in the path of travel of saidpivoted shoe to engage the shoe and hold the shoe and link inpredetermined relation to each other during a bending operation.
 15. Atool as described in claim 14 wherein said projection on the link is apin set into the link and extending outwardly from the face thereof. 16.A tool as described in claim 1 wherein said first handle diverges fromthe second handle.
 17. A tool as described in claim 1 wherein said firsthandle has a circular end portion against which the mandrel is seatedand said end portion is formed with a series of apertures disposedequi-distant from the axis and said mandrel carries a detent means forselective engagment in any one of the apertures.
 18. A tool as describedin claim 17 wherein said detent means is a spring pressed means disposedwithin the mandrel and has a reduced diameter part extended outwardlytherefrom for engagment in the apertures.